L has been steadily moving through the Montessori math materials, but she seemed to hit a road block once we got to the teens. No matter how many times I showed her the numbers and named them, she would still insist that 11 is a 1 and a 1, 12 is a 1 and a 2, 13 is a 1 and a 3, etc. While the Montessori teen board is traditionally taught all by itself, that wasn’t working for us. I knew that L needed it to be a little more concrete, so I brought in the bead bars.
I began by setting out all of the single digits on one side of our work mat with the empty teen board on the other side. I handed L the bead bars and asked her to match them to the correct numbers, which was very easy for her because of her previous work with the colored bead stair.
Our printable teen board was not quite long enough to fit all of the 10 bead bars on one side, so we alternated. Once the bead bars had all been matched, it was easier to see that we were combining the quantity of 10 with the quantity of 1 to make 11.
I pointed to the first number 10 and said, “10.” I picked up the 10 bead bar beside it and counted to 10. Then I pointed to the number 1 and said, “1.” I picked up the 1 bead bar and counted to 1. I placed the number 1 on top of the 0 in the 10 and said, “11.” Then I counted the ten and one bead bars together until I got to 11.
We continued in the same way with 12, but you know L — she quickly wanted to do it herself. When she placed the number 2 on top of the 0 in 10, she said, “Wait… a 1 and a 2?” In response, I took the 1 bead bar and the 2 bead bar and placed them together. Then I counted the beads: “1, 2, 3. A 1 and a 2 make 3. Is this number 3?” L knew that it wasn’t. I counted the 10 bead bar wth the 2 bead bar and showed her that it made 12. “A 10 and a 2 make 12.” And that’s where it clicked for her.
We continued naming and counting the whole way down the board…
…until all of the numbers and bead bars had been matched.
After many failed attempts on my part of finding a way to help L understand the concept of teens, the only way it finally clicked for her was when we combined Montessori materials. I have a feeling this is the way we will be learning all of the rest of the numbers, also — that 20 is two 10s, 21 is two 10s and a 1, 30 is three 10s, etc.
If you don’t want to purchase a Montessori teen board for home use, I found this one as a free printable. I just cut out each 10 and glued it all on some yellow cardstock with a bit of a border around each number to make it look more like the real thing.